'This is Us' season 1 episode 7 spoilers: Rebecca and Jack acknowledge their marital issues; Randall and Kevin's rocky relationship explained

Rebecca (Mandy Moore) and Jack (Milo Ventimiglia) begin noticing some distance between them in the upcoming episode of NBC's hit family drama "This is Us" season 1.
Titled "The Best Washing Machine in the Whole World," next week's episode will explore complicated relationships. According to the official synopsis for episode 7, the reason behind Randall (Sterling K. Brown) and Kevin's (Justin Hartley) rocky relationship will finally be explained. Beth (Susan Kalechi Watson) and William (Ron Cephas Jones) spend some time together, but the day takes a different turn when a secret William has been keeping is brought to light. As Rebecca prepares to get back to work after years of being a stay-at-home mother, both she and Jack acknowledge that there is some distance between them. Meanwhile, Toby (Chris Sullivan) gets caught straying from his diet regimen, putting Kate (Chrissy Metz) in a difficult spot.
In the previous episode, it was revealed that Randall actually has a decent relationship with his mother, although Rebecca's secret could threaten that. Although the storyline delved deeper into Rebecca and Kate's relationship, viewers have yet to see the dynamic between Rebecca and Kevin when he was a kid.
Executive producer Ken Olin recently caught up with Entertainment Weekly, and he revealed that Kevin's relationship will be tackled in the next episode. It will also give viewers an insight on what happened before Kevin's rocky relationship with his step-brother Randall.
"Yes, you begin to see that in the next episode... We begin to see not only how Kevin's relationship with Rebecca affected Kevin, but how Randall's relationship with Rebecca affected Kevin, and what we hinted at early on—the sense that he is not getting the attention that he needs or deserves—that we begin to see ways in which it's really impacted Kevin and Randall's relationship as adults," he said. "We really begin to look at the distance between the two of them."
Keep tuning in to "This is Us" season 1 every Tuesday night at 9 p.m. ET on NBC.